Question

A lake near Susan’s house is predicted to lose water every day because of a drought. The table shows the estimated water depth in feet, y, after x days of drought.



Choose the function that represents the data.

y = −0.5x + 100
y = −x0.5 + 100
y = −0.5x2 + 100

Answer 1

y = −0.5x + 100

Reason: the lake loses the same amount each day so y decreases at a constant rate (linear). The slope is the daily change (−0.5 ft/day) and the intercept is the depth at day 0 (100 ft). The other two are nonlinear (square‑root or quadratic) and would not produce equal day‑to‑day differences.